This invention relates to an apparatus for piercing a predetermined number of bags, each having a pair of holes punched in a lip portion, with wicket pins and stacking the bags onto the pins.
As stacking apparatus of this kind, there is known a conventional a system which sucks an individual finished bag by a suction member which rotates either in one direction or in both directions using a vacuum pump and which fits the bag onto wicket pins. According to this system, however, the suction member sometimes fails to perfectly suck the bag or bags, or the bags come off from the suction member or rub one another. In particular, when the sucking speed is increased in order to improve the production efficiency, the suction time becomes inevitably shorter whereby these tendencies are further promoted. If the suction member is of a one-way rotation type, the construction of the connection portion between the suction member and the vacuum pump becomes complicated. This also holds true if the suction member is of the type that rotates in both directions. Hence, with both types it is difficult to attain the high speed operation, and they call for a vacuum pump of a large scale, the result being generation of a great amount of noise and increased power consumption.
Another system has also been known in which, while both upper and lower end portions of a bag are clamped by clamp belts rotating continuously, the bags are continuously transferred onto the wicket pins and fitted and stacked onto the pins by means of pushers. According to this system, however, it is difficult to correctly fit the pair of holes of each bag to the wicket pins because the clamping of the bag and the fitting of the bag onto the wicket pins can not be carried out in a reliable manner owing to the rotation of the clamp belts.